1. Field of the Invention
This invention relates to a device for opening and closing a shutter member of a disk cartridge used in conjunction with a signal recording and/or reproducing apparatus. More particularly, it relates to such device adapted for opening and closing the shutter member mounted movably to the disk cartridge for opening and closing the signal read or write apertures on the upper and lower surfaces of a disk cartridge containing a disk such as optical or opto-magnetic disk.
In the present specification, the term "signal recording and/or reproducing apparatus" means a magnetic, an optomagnetic or an optical apparatus in the sense that it makes use of an optical magnetic or an opto-magnetic disk as the signal recording medium.
In the present specification, the term "cartridge housing" generally means the casing devoid of the shutter member and not containing the disk, whereas the term "disk cartridge" means the assembly of the housing, the shutter member and the disk.
2. Prior Art
Heretofore, optical or magnetic disk used as signal recording media for the signal recording and/or reproducing apparatus are contained in a cartridge housing for protecting their signal recording surfaces, and are mounted in the recording and/or reproducing apparatus while they are contained in this manner in the cartridge housing. The cartridge housing containing the disk is provided on its upper and lower surfaces with apertures confronted by a pickup unit, such as optical pickup unit designed to effect signal reading or signal writing operations when the disk cartridge is inserted into the recording and/or reproducing apparatus. There is slidably mounted on the cartridge housing shutter member adapted for closing the apertures in order to prevent injury of or dust deposition on the disk in the cartridge housing due to opening of the apertures unless the disk cartridge is mounted in the signal recording and/or reproducing apparatus. For this reason, a device for opening and closing the shutter member is provided on the recording and/or reproducing apparatus making use of the above described disk cartridge.
In the above described recording and/or reproducing apparatus making use of the disk cartridge as signal recording medium, reading or writing of information signals becomes possible only when the disk cartridge is correctly introduced in the recording and/or reproducing apparatus, the shutter member is opened by the opening and closing device to open the signal read or write apertures, and the pickup unit faces the disk through these apertures. Thus, when the disk cartridge is inserted incorrectly and placed in the recording and/or reproducing apparatus without the shutter member being opened by the opening and closing device, it becomes impossible to read or write information signals. In the case of the disk cartridge in which the apertures confronted by the disk table of the disk rotation drive unit and by the thrust member for thrusting the disk to the disk table are continuations of the signal read and write apertures and are also covered by the shutter member, it is not possible that the disk contained in the cartride be chucked to the disk rotation drive unit for rotation in unison therewith unless the shutter member is opened.
In the recording and/or reproducing apparatus making use of the aforementioned disk cartridge as the signal recording medium, such as the disk player, it is an essential requirement that the mounting of the disk cartridge in the disk mounting unit is enabled when the disk cartridge is correctly introduced into the device and that the mounting of the disk cartridge into the device is inhibited in case of incorrect insertion.